I ran across a stihl 650 with a 36 inch bar and chain. I was wondering what is the most anyone would give for this saw. It looks to be like new. It has a stihl bar and chain that looks to be "new" also. also is there really any differences in the 660 and 650?? and why would stihl make 2 saws that close in size?? Dont really know if I would have a use for such a big saw, but was thinking about running it and sale it if I dont ever find a use for it.